In order to carry out a reaction under high-temperature and high-pressure conditions, an autoclave apparatus, which is a high-pressure reactor, is required. Conventionally, horizontal autoclaves capable of increasing the capacity by increasing the length thereof while maintaining or even decreasing the diameter thereof have been widely used in order to manufacture a large-capacity autoclave apparatus. Such conventional horizontal autoclaves are disclosed in International Patent Publication No. 2015/021524, U.S. Patent Laid-Open Publication No. 2015/0086450, U.S. Pat. No. 9,732,400, and the like.
A common feature of these horizontal autoclaves is that the inside of one autoclave is divided into several small compartments, and each of the compartments is provided with a separate agitator, thereby integrating several autoclaves into a single unit. Such a horizontal autoclave may be advantageous in that it is easy to manufacture the horizontal autoclave since it is possible to increase an apparatus capacity by increasing the number of compartments even if the diameter thereof is small, and it is possible to drive a large capacity apparatus using small scale agitators.
However, in the case of horizontal autoclaves, it may be necessary to install a plurality of agitators in one apparatus and to install an apparatus for introducing oxygen or the like separately for each compartment, so that the number of necessary nozzles or the like may increase and the rate of operating the apparatus may be lowered due to frequent apparatus failure.
Further, in the case of horizontal autoclaves, the process solution, which has been reacted in each compartment, must be delivered over the upper portion of a blocking wall installed between adjacent compartments so as to be moved to the next compartment. However, because the upper portion of the blocking wall is exposed to a hot gas portion, a large amount of salt due to a process solution evaporation phenomenon may occur in the upper portion of the blocking wall.
Furthermore, due to the characteristics of the horizontal autoclave, a contact interface between the process solution and the gas layer in the upper portion is wide. Because the gas layer is maintained at a high temperature, a large amount of salt is precipitated by the process solution evaporation phenomenon on the surface of the process solution and a wall portion. When the precipitated salt grows in the form of lumps, it may cause an apparatus failure. Therefore, it may be necessary to stop operation of the apparatus periodically and perform maintenance for removing the precipitated salt. Therefore, horizontal autoclaves have a disadvantage in that apparatus operation efficiency is remarkably reduced.
In addition, because horizontal autoclaves have an inner structure which is partitioned by partition walls and angular corners are formed in the respective compartments, the process solution is not agitated well.